View Full Version : Impeller displacement got displaced !
08-07-2010, 12:57 AM
Working on a 19EA that showed a bearing alarm on the relay board. Closer diagnosis show that the impeller displacement safety switch was open. Pump over the refrigerant to the utility vessel and open up the compressor. The switch is definitely open. The little dittaleebob (technical term) on the end of the switch is rocked over. Thrust calls for .008-.014 of an inch tolerance and I measure .012 ". Machine is clean and smooth turning, Lab clearance is a bit excessive .013" gauge will circle around with a bit of tightness making a total of .026" . The trip lever (dittaleebob) had the .060" with the high speed shaft in the thrusted position. No radial play around the impeller and no marks or scratches on the wheel. Anybody have any explanations for what happened here. Thrust was taken inside inspection (gearbox) and on the rim (eye) of the impeller. It always came up with boxcars, .012". Thanks guys-GEO
08-08-2010, 12:13 PM
saw this once before where the switch tripped and no problems could be found, the tower fan had failed & the customers operators kept resetting
the high pressure switch & restarting the chiller, guess at each restart
the compressor got & bigger & longer.
08-09-2010, 07:30 PM
I am assuming that you have ....or will replace the displacement switch...
I would humbly suggest that the very tip end of the "Ditttaleebob" be closely examined for any possible contact...As the EA's do not have any eliminators over the evaporator tubes, it would not take too big a piece of debris, gasket chunk, 515 debris, rust, possum innards etc. to fill that .060 gap & trip the now famous "Dittaleebob"..
Other than that......I can only guess that Mssr. Dittaleebob got tired of standing erect & decided finally decided to take a break.....
08-09-2010, 09:22 PM
Under close examination there are no scratches or signs that anything hit the trip lever and the impeller shows no indication or blemish. So I guess we'll put it back together with a new Carrier part # BR549 "Dittaleebob" 1 each. I guess this is a learning experience as I have never used 515 on any high pressure machine. Thanks for the comeback -GEO
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